SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c443e7f55ff6c5572f75ea8189b7d91a3932d05e97d1d78ba79a346073b1ea9f' 
  AND token = 'uFvWTM2rfYQ+weSpXObB/j2+NcWrS5Nu0s1DiuUfEq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}